attach method
Registers the controller to a slider with the given extent and marks.
A controller can only be attached to a single slider at a time.
Implementation
@override
@internal
void attach(double extent, List<FSliderMark> marks) {
assert(marks.isNotEmpty, 'At least one mark is required.');
final proposed = DiscreteSelection(
mainAxisExtent: extent,
extent: selection.extent,
offset: selection.offset,
ticks: SplayTreeMap.fromIterable(marks.map((mark) => mark.value), value: (_) {}),
);
if (_selection == null) {
_selection = proposed; // We don't want to notify listeners when performing initialization.
} else {
selection = proposed;
}
}